The present disclosure relates to a power supply circuit, a power supply system, and an electric storage device suitable for forming a low voltage from a high voltage.
There are known series regulators in which a voltage control semiconductor element is connected in series to a load, a constant voltage is supplied to the semiconductor element by a constant voltage source, and a voltage to be applied to the load is constantly maintained (for example, see JP 2003-259632A). The series regulators can apply a constant voltage, for example, even when a load varies.